Louvered Pipe Shroud Assembly

ABSTRACT

Embodiments of an apparatus of the present invention generally include a filtration assembly having a louvered shroud circumferentially positioned around a perforated inner pipe, such that at least a substantial portion of the shroud&#39;s inner surface contacts and frictionally engages the outer surface of the inner pipe. Embodiments of a method of the present invention generally include spirally wrapping a substantially flat strip of louvered material around the inner pipe, wherein adjoining edges of the louvered material abut and are at least partially welded together, to provide the shrouded pipe. Other method embodiments generally include an inner pipe having a louvered shroud positioned there around being introduced to a device operable to, dynamically or statically, radially compress the shroud such that at least a substantial portion of the shroud&#39;s inner surface contacts and frictionally engages at least a substantial portion of the outer surface of the inner pipe.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Applications No.62/356,935, filed on Jun. 30, 2016, which application is incorporatedherein by reference as if reproduced in full below.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

FIELD OF THE INVENTION

The present invention relates generally to an apparatus and methods forfiltering fluid in a well bore. More specifically, the present inventionaddresses an apparatus which provides a louvered filtration surface andmethods of manufacturing same.

BACKGROUND

In subsurface oil and gas drilling operations, filters are typicallyemployed to prevent particulate matter from being entrained in the fluidproduct piped to the surface. To effectively screen fine particles, awoven filter medium may be utilized. Due to the strength concernsregarding woven filter media, perforated shrouds are utilized to protectthe filter medium. See, e.g., U.S. Pat. No. 6,382,318 to Whitlock.

In one known process, an outer perforated jacket is assembled over afilter medium, which is itself placed over a coarse support screen ordrainage layer by transversally wrapping a sheet of filter medium therearound, and this combination is advanced through a die such that inwardprotrusions of the jacket are mechanically compressed against the filtermedia to effect a seal of the subassembly. This subassembly can then beplaced on a perforated support pipe or may be formed on the perforatedsupport pipe. See, e.g., U.S. Pat. No. 6,305,468 to Broome, et al.

In another process, a filter medium is cold-rolled with a perforatedmetal shroud material and spiral-wound, around an inner support orwithout an inner support, to form a filter cartridge. In suchapplication, adjoining longitudinal edges of spirally-wound filtermedium overlap and adjoining longitudinal edges of spirally-wound shroudmaterial are welded together. The filter cartridge can then be slid ontoa base pipe. See U.S. Pat. No. 7,287,684 to Blackburne, Jr.

In yet another process, two offset filter medium layers are spirallywrapped around a spirally wire-wrapped drain filter, and a spirallywire-wrapped cover filter is provided over the filter medium layers. SeeU.S. Patent Application Publication No. 2015/0238884 to Vu.

By another known technology, sub-surface filtration is accomplished byuse of a slotted pipe (“slotted liner”) which has longitudinally cutslots along the length of the piping sections. See, e.g., U.S. Pat. No.1,135,809 to Jones. Typically, the slotted liner is provided bymachining multiple longitudinal slots throughout the length andcircumference of each pipe section. Limitations of using slotted linersinclude, however, poor slot dimension precision, pluggage issues, highpressure drop, and a maximum flow area of only 2-3% of the pipe surface.

While these filtration systems may be useful, it would be advantageousto provide a filtration apparatus having only a single outer componentand capable of providing acceptable filtration performance.

BRIEF SUMMARY OF THE INVENTION

Embodiments of an apparatus of the present invention generally comprisea filtration assembly comprising a louvered shroud circumferentiallypositioned around a perforated inner pipe, such that at least asubstantial portion of an inner surface of the shroud contacts andfrictionally engages the outer surface of the inner pipe. One embodimentof a method of the present invention generally comprises spirallywrapping a flat strip of louvered material around the inner pipe,wherein adjoining edges of the louvered material are welded together.Another embodiment of a method of the present invention generallycomprises providing an inner pipe and a louvered shroud positioned therearound to a device operable to dynamically radially compress the shroudsuch that at least a substantial portion of an inner surface of theshroud contacts and frictionally engages the outer surface of the innerpipe. Still another embodiment of a method of the present inventiongenerally comprises providing an inner pipe and a louvered shroudpositioned there around to a device operable to statically compress theshroud such that at least a substantial portion of an inner surface ofthe shroud contacts and frictionally engages the outer surface of theinner pipe.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the exemplary embodiments,reference is now made to the following Description of ExemplaryEmbodiments of the Invention, taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 depicts an embodiment of a shroud section of the presentinvention.

FIG. 2 depicts an embodiment of formation of a shroud section.

FIG. 2A depicts an alternative embodiment of formation of a shroudsection.

FIG. 3 depicts an embodiment of a shroud section disposed on a pipesection.

FIG. 4 depicts an embodiment of formation of a shroud section on a pipesection.

FIG. 5 depicts an embodiment of a shrouded pipe section beingcircumferentially reduced using a tube reduction mill.

FIG. 6 shows another view of the tube reduction mill of FIG. 5.

FIG. 7 depicts an end view of an embodiment of a shrouded pipe section.

FIG. 8 depicts an embodiment of a shrouded pipe section beingcircumferentially reduced using a static die.

FIG. 8A shows another view of the static die of FIG. 8.

FIG. 9 shows another view of an embodiment of a shrouded pipe sectionbeing circumferentially reduced using a static die.

FIG. 10 depicts an embodiment of a shroud section louver.

FIG. 10A shows another view of the shroud section louver of FIG. 10.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE INVENTION

The exemplary embodiments are best understood by referring to thedrawings with like numerals being used for like and corresponding partsof the various drawings. Use of relative terms herein, such as “top,”“bottom,” “upper,” “lower,” “right,” “left,” and the like, are used forillustrative purposes only are not intended to limit the invention to adisclosed orientation or arrangement.

In various embodiments of the present invention, a louvered shroudsection is provided circumferentially around a pipe section. In anembodiment depicted in FIG. 1, a louvered shroud section 2 comprises asubstantially tubular component comprising an exterior surface 4. In oneembodiment, exterior surface 4 comprises a plurality of louvers 6comprising indentations 8. In one embodiment, a louver 6 comprises anindentation 8 comprising a portion of the exterior surface 4 angledinwardly toward an interior 10 of tubular shroud section 2. In oneembodiment, a louver 6 comprises one or more apertures 12 within theindentation 8 (see FIGS. 10 and 10A). Apertures 12 allow for fluid flowbetween the exterior of shroud section 2 and an interior 10 of shroudsection 2.

In one embodiment, shown in FIG. 2, shroud section 2 is produced byspirally cold-rolling lengths of a substantially planar material 22containing a plurality of louvers 6 around a forming mandrel 13 to forma tubular shroud section 2. In one embodiment, shown in FIG. 2A, shroudsection 2 is produced by spirally cold-rolling lengths of asubstantially planar material 22 containing a plurality of louvers 6without use of a forming mandrel 13 to form a tubular shroud section 2.In the embodiments of FIGS. 2 and 2A, material 22 is provided in coiledform, although other arrangements may be employed. Although theembodiments of FIGS. 2 and 2A depict spirally wrapping material 22, theinvention is not so limited and other orientations of material 22 may beemployed, such as but not limited to, axially wrapping one or moresheets of material 22 around pipe 14 or a forming mandrel 13. In oneembodiment, the material comprises steel, although other materials maybe employed, as would be understood by one skilled in the art. In oneembodiment, the material comprises stainless steel.

In one embodiment, louvers 6 are pre-formed in the material by providingindentations 8 through “punching” a surface of a section of material 22,although other methods of forming indentations 8 may be utilized, aswould be understood by one skilled in the art. In one embodiment, shownin detail in FIGS. 10 and 10A, a punched indentation 8 comprisessubstantially parallel “top” edge 9 a and “bottom” edge 9 b, wherein adepressed section 11 remains connected thereto there between. In oneembodiment, substantially parallel “left” edge 15 a and “right” edge 15b border a created aperture 12. In other embodiments (not shown),louvers 6 and/or indentations 8 may comprise different physicalfeatures.

The number, orientation, and positioning of indentations 8 may be variedas required for a particular application. In the embodiment depicted inFIG. 2, the indentations 8 protrude inward in the coiled material 22;i.e., upward away from surface 26, such that upon formation of shroudsection 2 the indentations 8 extend inwardly toward interior 10 ofshroud section 2. This provides the louvered apertures 12 in shroudsection 2.

In one embodiment, coiled material 22 is provided to a spiral tubewelding machine (not shown) equipped with a forming mandrel 13 sized fora desired shroud section diameter. In one embodiment, material 22 isprovided to the spiral tube welding machine by means of power pinchrollers 23 configured to correspond to the desired radius of shroudsection 2. In one embodiment, the material 22 is spirally wrapped suchthat adjacent edges 24 abut each other. In one embodiment, material 22is provided through one or more guides 25 to assist in providingmaterial at the desired angle. In one embodiment, at least a portion ofabutting edges 24 of the wrapped material are affixed to each other,such as by welding. In one embodiment, when sufficient material 22 hasbeen wrapped around mandrel 13 to produce a shroud section 2 of desiredlength, the mandrel 13 is removed and the ends 58 of shroud section 2are trimmed to provide a uniform length thereof. Similarly, in anembodiment where a mandrel is not employed, when sufficient material 22has been pre-formed through the pinch rollers 23 to form the desireddiameter to produce a shroud section 2 of desired length, the ends 58 ofshroud section 2 are trimmed to provide a uniform length thereof.

While the indentations 8 in FIG. 2 are depicted as substantiallyrectangular and oriented lengthwise parallel to the longitudinal axis ofshroud section 2, such depiction is only exemplary and other shapesand/or orientations are contemplated. In addition, the pattern orpatterns of indentations 8 in exterior surface 4 of shroud section 2 maybe regular or irregular.

Referring to FIG. 3, a shrouded pipe section 30 comprises a shroudsection 2 disposed circumferentially around a pipe section 14. In oneembodiment, pipe section 14 may comprise any substantially tubularstructure containing one or more orifices 16 in the exterior surface 18thereof (see FIG. 4). In one embodiment, pipe section 14 comprisesperforated pipe. As described in more detail below, shroud section 2 maybe provided on pipe section 14 by different means.

In one aspect, apertures 12 act to filter fluid flowing between theexterior of shroud section 2 and the interior 10 thereof. Thus, thedimensions of apertures 12 at least partially determine the effectivefiltration capability of shroud section 2.

In one embodiment, fluid communication between the interior 10 of shroudsection 2 and an interior 20 of pipe section 14 is achieved via the oneor more orifices 16 disposed in the exterior surface 18 of pipe section14. In one embodiment, a substantial portion of interior surfaces 28 ofdepressed sections 11 of shroud section 2 (see FIGS. 10 and 10A) arefrictionally engaged with a substantial portion of the exterior surface18 of pipe section 14, i.e., shroud section 2 is in an interference fittherewith.

In one embodiment, shown in FIG. 4, shroud section 2 is provided on pipesection 14 by direct spiral wrapping of material 22 onto pipe section14. Similar to as described above with respect to FIG. 2, in oneembodiment direct wrapping of pipe 14 comprises spirally cold-rollinglengths of a material 22, containing a plurality of louvers 6, directlyaround pipe section 14 to form a tubular shroud section 2 there around.In one embodiment, at least a portion of abutting edges 24 of material22 are affixed to each other, such as by welding. Such affixation may beperformed during the direct wrapping process. In one embodiment, anyexcess material 22 at one or both ends 58 of shroud section 2 may betrimmed to provide a uniform length shroud section 2. In one embodiment,providing shroud section 2 on pipe section 14 by directly wrappingproduces an interference fit between the interior surfaces 28 ordepressed sections 11 of shroud section 2 and the exterior surface 18 ofpipe section 14. In one embodiment, after shroud section 2 is providedaround pipe section 14 in an interference fit, shroud section 2,proximate either or both ends thereof, may be affixed to pipe section14. In one embodiment, such affixation comprises welding to the exteriorsurface 18 of pipe section 14. In another embodiment, an interferencefit end ring 59 may be provided on circumferentially to one or both ends58 of shroud section 2 and welded to the exterior surface 18 of pipesection 14.

In one embodiment, a pre-formed shroud section 2 is slid longitudinallyover a pipe section 14 to form a slid-over shrouded pipe section 30. Inone embodiment, pipe section 14 comprises pin (male) connectors ateither end thereof, while in other embodiments, one or both ends of pipesection 14 may comprise a coupling (female) component, which may beprovided on pipe section 14 or may be integral therewith. For simplicityof description only, reference to the ends of pipe section 14 will be toa pin end 32 and a coupling end 34. In one embodiment, the sliding ofshroud section 2 over pipe section 14 comprises sliding the shroudsection 2 from the pin end 32 of the pipe section 14 toward the couplingend 34 of the pipe section. The shroud section 2 is then positioned apredetermined distance from the coupling end 34 and the pin end 32 ofthe pipe section 2.

Provision of shroud section 2 onto pipe section 14 by such sliding meansmay result in gaps 76 between the interior surfaces 28 of depressedsections 11 and the exterior surface 18 of pipe section 14. In oneaspect, even if such gaps 76 are not created, the sliding of shroudsection 2 onto pipe section 14 may not effectuate an interference fitthere between. In various embodiments of the present invention, adesired interference fit between shroud section 2 and pipe section 14may be accomplished by radial compression of a slid-over shrouded pipesection 30, thereby providing circumferential reduction of shroudsection 2.

In one embodiment, the shroud section 2 of a slid-over shrouded pipesection 30 is affixed to the exterior surface 18 of pipe section 14 onthe leading end of pipe section 14 that is to be provided forcircumferential reduction. In one embodiment, the pin end 32 is utilizedas the leading end. In one embodiment, such affixation comprises tackwelding shroud section 2 to the exterior surface 18 of pipe section. Theslid-over shrouded pipe section 30 may then be provided to a deviceoperable to dynamically or statically compress the shroud section 2 suchthat a substantial portion of inner surface 28 of depressed sections 11of the shroud section 2 contacts and frictionally engages the exteriorsurface 18 of the pipe section 14, i.e., produces an interference fitthere between.

Now referring to FIG. 5, in one embodiment, the slid-over shrouded pipesection 30 is advanced, one or more times, through one or moretube-reduction mills 38 to dynamically achieve an interference fit ofshroud section 2 around pipe section 14. Tube reducing mills aregenerally known in the art. See, for example, U.S. Pat. No. 8,166,789 toOkui, et al., U.S. Pat. No. 5,533,370 to Kuroda, et al., and U.S. Pat.No. 4,260,096 to Samarynov, et al., each of which is incorporated byreference herein in its entirety. Suitable tube reduction mills areavailable from Addison Machine Engineering, Inc. of Reedsburg, Wis.

In one embodiment, tube reduction mill 38 comprises a plurality ofsubstantially circular shaped rollers 40, each comprising a concaveexterior groove 42. In the embodiment shown in FIG. 5, reduction mill 38comprises four rollers 40 positioned at 90° angles to each other,although other orientations may be employed. In other embodiments (notshown), reduction mill 38 may comprise more or fewer rollers 40, whichmay be symmetrically or unsymmetrically oriented. In the embodiment ofFIG. 5, the rollers 40 are disposed such that a centralized,substantially circular mill opening 44 (shown in detail in FIG. 6) iscreated by grooves 42 via positioning of the rollers 40. The individualrollers 40 are adjusted to form the desired mill opening 44 diameter 46.As would be understood by one skilled in the art, a tube reduction mill38 may comprise various mechanisms (not shown) for controlling thedimensions of mill opening 46 and advancing a slid-over shrouded pipesection 30 there through. In other embodiments (not shown), separatemeans for advancing a slid-over shrouded pipe section 30 through a tubereduction mill 38 may be employed.

In one embodiment, opposing rollers 40 a, 40 c, and/or 40 b, 40 d (shownin FIG. 6), of tube reduction mill 38 may be adjusted in tandem throughcontrol of tube reduction mill 38. In one embodiment, control of rollers40 may include utilization of a mechanism comprising one or moremicrometers. In one embodiment, control of tube reduction mill 38comprises use of a pressure measurement device, such as, but not limitedto, a load cell, to determine pressure between the exterior surface 4 ofshroud section 2 and one or more rollers 40.

Before introduction of slid-over shrouded pipe section 30 to tubereduction mill 38, that component comprises an initial shroud section 2outer diameter 48, as shown in FIG. 7, which includes the outer diameter50 of pipe section 14, twice the thickness 52 of shroud section 2, aswell as any gaps 76 between the interior surface 28 of depressedsections 11 of shroud section 2 and the exterior surface 18 of pipesection 14. In one aspect, the diameter 46 of mill opening 44 determinesa reduced outer shroud diameter 54 which the circumferentially reducedshrouded pipe section 30 comprises upon exiting tube reduction mill 38.

Reference to the diameter 46 of mill opening 44 as determinative of thereduced outer shroud diameter 54 of circumferentially reduced shroudedpipe section 30 presumes that the mill opening 44 employed issubstantially round; however, other geometries of slid-over shroudedpipe section 30 are suitable for the such circumferential reductionusing tube reduction mill 38, in which case the cross-sectional area oftube reduction mill 38 opening 44, whatever shape that might comprise,will determine the outer dimensions of the circumferentially reducedshrouded pipe section 30. Accordingly, in one embodiment, grooves 42 ofrollers 40 may have differing depths and/or geometries.

In one embodiment, as shown in FIG. 5, slid-over shrouded pipe section30 is introduced to, and advanced through, tube reduction mill 38,thereby reducing initial shroud outer diameter 48 to a reduced outershroud diameter 54. In one aspect, this provides an interference fit ofshroud section 2 around pipe section 14. If the desired fit is notachieved, the configuration of tube reduction mill 38 opening 44 can beadjusted, whereupon the slid-over shrouded pipe section 30 isre-introduced to, and advanced through, tube reduction mill 38 toachieve the desired fit.

In one aspect, radial compression of slid-over shrouded pipe section 30achieved by the operation of tube reduction mill 28 may comprisesufficient compressive force to deform louvers 6, and thereby change thedimensions of apertures 12. In one embodiment, all or substantially allgaps 76 are eliminated through effected contact between the interiorsurfaces 28 of depressed sections 11 of shroud section 2 and theexterior surface 18 of pipe section 14. In any embodiment where shroudsection 30 has been elongated by operation of tube reduction mill 38,excess length of circumferentially reduced shroud section 2 may betrimmed. In one embodiment, such trimming provides a desirednon-shrouded length 56 between end 58 of shroud section 2 and end 60 ofcoupling end 34 end of pipe section 14. In one embodiment, both ends ofthe shroud section 2 are then welded to the exterior surface 18 of pipesection 14.

Referring now to FIG. 8, in one embodiment, the slid-over shrouded pipesection 30 is advanced, one or more times, through one or more staticdies 62 to statically provide the circumferential reduction required toachieve an interference fit of shroud section 2 around pipe section 14.Examples of static dies are disclosed in the abovementioned U.S. Pat.No. 6,305,468 Broome, et al., and in U.S. Pat. No. 5,611,399 to Richard,et al., each of which is incorporated by reference herein in itsentirety.

In one embodiment, a substantially annular static die 62 comprises asubstantially round die opening 64 comprising a fixed exit diameter 66(see also FIGS. 8A and 9). In one embodiment, static die 62 is affixedto a support structure (not shown) to stabilize the static die 62. Inone embodiment, a means (not shown) of advancing slid-over shrouded pipesection 30 through static die 62 is provided. In one embodiment, shownin detail in FIG. 8A, the structure of static die 62 is configured suchthat an entry diameter 67 is greater than an exit diameter 66. Asdescribed above with regard to utilization of tube reduction mill 38,slid-over shrouded pipe section 30 comprises an initial shroud section 2outer diameter 48, as shown in FIG. 7, that includes the outer diameter50 of pipe section 14, twice the thickness 52 of shroud section 2, aswell as any gaps 76 between the interior surfaces 28 of depressedsections 11 of shroud section 2 and the exterior surface 18 of pipesection 14. In one aspect, the exit diameter 66 of static die opening 62determines the reduced outer shroud diameter 54 which thecircumferentially reduced shrouded pipe section 30 comprises uponexiting tube static die 62.

Reference to the exit diameter 66 of static die opening 62 asdeterminative of the reduced outer shroud diameter 54 ofcircumferentially reduced shrouded pipe section 30 presumes that thestatic die 62 opening 64 employed is substantially round; however, othergeometries of slid-over shrouded pipe section 30 are suitable for thesuch circumferential reduction using static die 62, in which case thecross-sectional area of static die 62 opening 64, whatever shape thatmight comprise, will determine the outer dimensions of thecircumferentially reduced shrouded pipe section 30.

In one embodiment, a slid-over shrouded pipe section 30 is produced asdescribed above. In one embodiment, as shown in FIGS. 8 and 9, slid-overshrouded pipe section 30 is introduced to, and advanced through, staticdie 62, thereby reducing initial shroud outer diameter 48 to a reducedouter shroud diameter 54. In one aspect, this provides an interferencefit of shroud section 2 around pipe section 14. If the desired fit isnot achieved, the exit diameter 66 of static die 62 opening 64 may bereduced, whereupon the slid-over shrouded pipe section 30 isre-introduced to, and advanced through, static die 62 to achieve thedesired fit.

In one aspect, radial compression of slid-over shrouded pipe section 30achieved by the operation of static die 62 may comprise sufficientcompressive force to deform louvers 6, and thereby change the dimensionsof apertures 12. In one embodiment, all or substantially all gaps 76 areeliminated through effected contact between the interior surfaces 28 ofdepressed sections 11 of shroud section 2 and the exterior surface 18 ofpipe section 14.

As described above, in any embodiment where shroud section 30 has beenelongated by operation of static die 62, excess length ofcircumferentially reduced shroud section 2 may be trimmed. In oneembodiment, such trimming provides a desired non-shrouded length 56between end 58 of shroud section 2 and end 60 of coupling end 34 of pipesection 14. In one embodiment, both ends of the shroud section 2 arethen welded to the exterior surface 18 of pipe section 14.

Although the circumferential reduction methods outlined above have beendescribed as mutually exclusive of each other, the invention is not solimited and such methods may be combined; i.e., a slid-over shroudedpipe section 30 may be circumferentially reduced using a tube reductionmill, and then the once circumferentially reduced shrouded pipe section30 may be further circumferentially reduced using a static die, and viceversa. In addition, multiple utilizations of one or both methods may becombined.

As one objective in producing a shrouded pipe section 30, wherein thepipe shroud section 2 is disposed in an interference fit with a pipesection 14, is to provide a filtration mechanism around at least aportion of pipe section 14, the dimensions of aperture 12 are importantin defining the filtration capabilities of the shrouded pipe section 30.Accordingly, it may be desired to carefully control the accuracy andprecision of forming apertures 12 and/or the precision of alteringapertures 12 during a radial circumferential compression.

Referring to FIGS. 10 and 10, in one embodiment, a determination ofaperture 12 size is accomplished by measuring a louver 6 depth 70. Inone embodiment, louver 6 depth 70 is measured using a thread depthmicrometer. Other methods of measuring louver depth may be employed,including but not limited to, measurement using a laser or other lightor electromagnetic wave system. In one aspect, the louver 6 depth 70minus the thickness 52 of shroud section 2 equals the aperture 12 depth74. In one embodiment, a precision in indentation 8 formation, and/oralteration during a radial circumferential compression operation, allowsfor control of filtration capabilities of shrouded pipe section 30without requiring more detailed measurement of the cross-sectional areaof aperture 12; that is, consistency in aperture depth 74, along theright edge 15 a and left edge 15 b of louver 6 permits measurement ofaperture depth 74 be limited to one measurement thereof along anaperture 12. In one embodiment, such measurement is performed at a pointsubstantially equidistant from top edge 9 a and bottom edge 9 b.

Operational control of the methods of producing a finished shrouded pipesection 30 is desired to insure provision of a filtration mechanism ofprescribed capabilities. When the shrouded pipe section 30 is providedutilizing the direct wrapping method, measurements and calculations,including slot depth calculations, are performed to determine whetherthe finished shrouded pipe section 30 possesses desired characteristics.If undesired aperture 12 dimensions are obtained, changes to the processmay be undertaken as corrective action to provide a desired aperturedepth 74. In addition, a shrouded pipe section 30 provided utilizing thedirect wrapping method may be introduced to a radial compressionmechanism to affect necessary changes in desired characteristics.

When the interference fit shrouded pipe section 30 is provided utilizinga radial compression method, measurements and calculations, includingslot depth calculations, may be performed on the pre-formed shroudsection 2 and/or the slid-over shrouded pipe section 30 and/or thecircumferentially reduced shrouded pipe section 30 to determine whetherthat component possesses the desired louver characteristics for aparticular stage of the process. Because radial compression of slid-overshrouded pipe section 30 achieved by the operation of a tube reductionmill 38 and/or a static die 62 may comprise sufficient compressive forceto deform louvers 6, and thereby alter the dimensions of apertures 12,control of the radial compression process is desirable.

When a tube reduction mill 38 is being employed to produce a shroudedpipe section 30, control of operational parameters includes, but is notlimited to, adjustment of one or more rollers 40 to effect a change inthe dimensions of mill opening 44. In one embodiment, such adjustmentsmay be performed during the radial compression process. In oneembodiment, such control may comprise use of a pressure measurementdevice, such as, but not limited to, a load cell, to determine pressurebetween the exterior surface 4 of shroud section 2 and one or morerollers 40. Accordingly, such pressure measurements may be utilized toadjust the dimensions of mill opening 44 to provide desired aperture 12depth 74. In one embodiment, predictive calculations and/or historicaldata may be employed to program a desired pressure scheme such thatobtained pressure measurements can be compared to programmed parametersand deviations therefrom can us used, directly or indirectly,automatically or manually, to adjust tube reduction mill 38 controlparameters, including but limited to, the dimensions of mill opening 44.

In one embodiment, a method of the present invention comprises providinga louvered material and directly spirally wrapping the material around aperforated pipe section, such that an interference fit between a portionof the material and the exterior of the pipe is achieved, therebyproducing a louvered shrouded pipe section.

In one embodiment, a method of the present invention comprises providinga louvered shroud section, sliding the shroud section over a pipesection to form a slid-over shrouded pipe section, and radiallycompressing, statically or dynamically, the slid-over shrouded pipesection to produce a louvered shrouded pipe section having aninterference fit between a portion of the interior surface of the shroudsection and the exterior of the pipe.

While the preferred embodiments of the invention have been described andillustrated, modifications thereof can be made by one skilled in the artwithout departing from the teachings of the invention. Descriptions ofembodiments are exemplary and not limiting. Disclosure of existingpatents, publications, and known art are incorporated herein byreference to the extent required to provide details and understanding ofthe disclosure herein set forth.

We claim:
 1. A louvered shrouded pipe section, comprising: asubstantially tubular shroud comprising an exterior surface comprising aplurality of louvered apertures disposed thereon, wherein said aperturesallow fluid communication between the exterior of said shroud and theinterior of said shroud; and a substantially tubular pipe sectioncomprising an exterior surface comprising a plurality of orificesdisposed thereon, wherein said orifices allow fluid communicationbetween the exterior of said pipe section and the interior of said pipesection; wherein: said shroud circumferentially encompasses at least aportion of said pipe section; at least a portion of an inner surface ofsaid shroud contacts and frictionally engages said exterior surface ofsaid pipe section; and fluid communication is provided between saidexterior of said shroud and an interior of said pipe, via said aperturesand said orifices.
 2. The louvered shrouded pipe section of claim 1,wherein one or more of said louvered apertures comprise an indentationcomprising a portion of said exterior surface of said louvered shroudangled inwardly toward said interior of said shroud.
 3. The louveredshrouded pipe section of claim 1, wherein said tubular shroud is affixedto said exterior surface of said pipe section proximate either or bothends of said tubular shroud.
 4. The louvered shrouded pipe section ofclaim 1, wherein one or more of said louvered apertures is formed insaid shroud by punching said exterior surface of said louvered shroud.5. The louvered shrouded pipe section of claim 4, wherein at least onesaid aperture formed by punching comprises an indentation comprising afirst edge and a second edge parallel to each other, and a depressedsection connected between said first edge and a second edge.
 6. Thelouvered shrouded pipe section of claim 5, wherein said depressedsection, between a location of connection with said first edge and alocation of connection with said second edge, is substantially planar.7. A method of producing a louvered shrouded pipe section, comprising:providing a substantially planar material comprising a surfacecomprising a plurality of louvered apertures; and spirally wrapping saidmaterial around a substantially tubular pipe section, wherein said pipesection comprises an exterior surface comprising a plurality of orificesdisposed thereon, thereby forming a louvered shroud circumferentiallyaround said pipe section; wherein: at least a portion of an innersurface of said shroud contacts and frictionally engages said exteriorsurface of said pipe section; and fluid communication is providedbetween the exterior of said shroud and an interior of said pipe, viasaid apertures and said orifices.
 8. The method of claim 7, wherein saidspirally wrapping said material around a substantially tubular pipesection comprises cold rolling said material.
 9. The method of claim 7,wherein one or more of said louvered apertures comprise an indentationcomprising a portion of said exterior surface of said louvered shroudangled inwardly toward said interior of said shroud.
 10. The method ofclaim 7, further comprising affixing said tubular shroud to saidexterior surface of said pipe section proximate either or both ends ofsaid tubular shroud.
 11. The method of claim 7, wherein one or more ofsaid louvered apertures is formed in said shroud by punching saidexterior surface of said louvered shroud.
 12. The method of claim 11,wherein at least one said aperture formed by punching comprises anindentation comprising a first edge and a second edge parallel to eachother, and a depressed section connected between said first edge and asecond edge.
 13. The method of claim 12, wherein said depressed section,between a location of connection with said first edge and a location ofconnection with said second edge, is substantially planar.
 14. A methodof producing a louvered shrouded pipe section, comprising: providing asubstantially tubular shroud comprising a plurality of louveredapertures; advancing said shroud over a substantially tubular pipesection, wherein said pipe section comprises an exterior surfacecomprising a plurality of orifices disposed thereon, thereby forming alouvered shrouded pipe section; and radially circumferentiallycompressing said louvered shrouded pipe section by advancing saidlouvered shrouded pipe section through at least one compression device;whereby: at least a portion of an inner surface of said shroud contactsand frictionally engages an exterior surface of said pipe section; andfluid communication is provided between the exterior of said shroud andan interior of said pipe, via said apertures and said orifices.
 15. Themethod of claim 14, comprising affixing said tubular shroud to saidexterior surface of said pipe section proximate a lead end thereof priorto radially circumferentially compressing said louvered shrouded pipesection.
 16. The method of claim 14, wherein said compression devicecomprises a tube-reduction mill.
 17. The method of claim 16, whereinsaid tube-reduction mill comprises four rollers positioned at ninetydegree angles to each other.
 18. The method of claim 16, wherein saidtube-reduction mill is controllable utilizing a pressure measurementdevice.
 19. The method of claim 14, wherein said compression devicecomprises a static die.
 20. The method of claim 14, wherein saidradially circumferentially compressing said louvered shrouded pipesection elongates said shroud, and an excess length of said shroud iseliminated.